Process and a device for exactly holding the vertical excavating direction of a diaphragm wall

ABSTRACT

A process for exactly holding the vertical excavation direction of a diaphragm wall using a hydraulic diaphragm wall grab cooperating with an excavator and having an outer guide body and an inner body for receiving the grab appliance is improved and rendered considerably more efficient by the fact that the vertical position of the inner body and/or the guide body is continuously controlled by means of an inclination detector whose-signals are transferred to a controller which, in case the bodies of the grab deviate from the predetermined vertical position, compensates said deviation by swivelling the inner body relative to the guide body in opposite direction to the deviation.

The present invention relates to a process and a device for exactlyholding the vertical excavation direction of a diaphragm wall using ahydraulic diaphragm wall grab cooperating with an excavator and havingan outer guide body and an inner body receiving the grab appliance.

Diaphragm walls and sealing walls have become an important component infoundation engineering. Normally, a diaphragm wall is constructed insingle segments. In principle their depth is not definite, however, incase of greater depths there is the risk that diaphragm wall elements"run off" which, due to the deviation from the desired verticalposition, results in gaps between the segments in the lower region ofthe wall, impairing the stability of the wall to be built. Theconstruction of diaphragm walls having a depth of more than 40 mrequires special experience and measures during excavation, for example,extensive measurements at the open slots. These are excavated withoutlining and, in case of inhomogeneous soil, tend to deviate from thepredetermined vertical direction for this reason.

Usual widths of diaphragm walls amount to 600-800 mm, however, widths of400-1,500 mm can also be found in construction work, depending on thedepth and purpose of the diaphragm wall, In case a diaphragm wallsegment deviates from the predetermined vertical direction it isnecessary to cut the walls again using. profile chisels, in order toobtain a perfect vertical position of the wall. This process istime-consuming and increases construction expenses; for this reason thesite supervision strives to hold the diaphragm wall excavation in thepredetermined direction as exactly as possible.

It is known from the prior art to provide diaphragm wall grabs withso-called control plates mounted at the base frame. Such an arrangementis described, e.g., in the Special Print 66 of the Salzgitter gitterMaschinen AG, in the article "Anbaugerate fur Bagger" "Attachments forExcavators"!, Special appliances for drilling and building activities,by Dr.-Ing. Hans Bartholmai, illustrated on page 6, picture 15.

This equipment is suited to stabilize the vertical position duringexcavation of a diaphragm wall, however, it is unsuited to compensate analready existing deviation from the predetermined working direction.

It is the object of the present invention to provide a process and adevice for exactly holding the vertical excavating direction of adiaphragm wall by means of a diaphragm wall grab, allowing primarily toimmediately recognize any deviation from the predetermined excavatingdirection and to indicate same to the control panel of the diaphragmwall grab operator and secondarily to compensate said deviation by amodification of the direction of the grab.

In a process according to the introductory part of claim 1 this problemis solved according to the present invention by the fact that thevertical position of the inner body and/or guide body is continuouslycontrolled by means of an inclination detector whose signals aretransferred to a control unit and that, in case the bodies deviate fromthe predetermined vertical direction, this deviation is compensated byswivelling the inner body inversely to the deviation, relative to theguide body.

With this process the vertical excavating direction of a diaphragm wallcan for the first time be held automatically exact by using a hydraulicdiaphragm wall grab. This allows an efficient advance during theexcavation of a diaphragm wall by avoiding both the expensive andtime-consuming intermittent measuring of the excavated diaphragm wallpart and subsequent work; additionally continuously advancing excavationcan be carried out at a considerable cost reduction.

According to an embodiment of the present invention it is provided thatany possible angular deviation from the vertical position is combinedwith a depth measuring device related to the diaphragm wall grab, acoordination of deviation and diaphragm wall depth is calculated andthat this is indicated to the control panel of the diaphragm wall graboperator.

A device for exactly holding the vertical excavating direction of adiaphragm wall using a hydraulic diaphragm wall grab cooperating with anexcavator and a guide body related to said grab, wherein said body isdimensioned according to the width of the grab shovels and is providedat its top with a mounting for suspension to a carrying rope arrangementor to a telescopic rod assembly is characterized according to thepresent invention by the following features:

that the guide body forms an outer frame in which an inner body withhinged grab shovels and a hydraulic operating device is arranged;

that the inner body within the guide body is pivoted in crosswisedirection to the vertical course of the supporting wall by means ofhorizontal journals which are located in the direction of the diaphragmwall;

that hydraulic swing mechanisms are provided between the guide body andthe inner body;

that a detector to control the vertical position is located at the innerbody and/or guide body, and the excavator is provided with a controlunit governed by the detector to operate the swivelling mechanisms.

In contrast to the known grab appliance guidance by means of rigidcontrol plates, the inclination-controllable construction of thediaphragm wall grab according to the present invention can provide anextremely exact, sensitive and automatic vertical control of the grabappliance.

According to another embodiment it is provided that a depth measuringdevice is allocated to the diaphragm wall grab and that means areprovided by which the indication of both the position detector and thedepth measuring device can be mapped on each other.

By means of this device the excavator driver operating the diaphragmwall grab can always recognize whether the diaphragm wall in theexcavation is within the predetermined position allowances at therespective depth and whether and which adjustments have be carried out.

For this purpose, it is provided according to another embodiment thatmeans for an overriding manual regulative operation from the excavatorcontrol stand are allocated to the swing mechanism and to the controlunit governing said swing mechanism; these means allow a correction ofthe grab direction according to the indication of the detector.

Furthermore, it is provided that a hydraulic piston/cylinder-unit ishinged to the left and to the right side of the guide body frame asmeans for mutually swivelling the guide body and the inner body; saidunit interacts with an articulated lever arrangement which is alsopivoted at the frame and has a cam which can be set in reciprocatingswivelling movements and engages into a U-shaped guidance of theinternal body and swivels same in accordance with the position of thecam relative to the guide body from the orthogonal position into adifferent swivelling position corresponding to an adjustment angle.

Preferred embodiments of the present invention are illustrated inschematic drawings illustrating additional advantageous details of thepresent invention:

FIG. 1 illustrates the projection of a diaphragm wall grab in transversedirection to the diaphragm wall;

FIG. 2 represents a side view of the diaphragm wall grab according toFIG. 1 from a viewing direction along the diaphragm wall, with the guidebody and inner body non-swivelled;

FIGS. 3 and 4 are side views according to FIG. 2, however, with theinner body swivelled relative to the guide body by an adjustment angleα;

FIG. 5 shows a slightly different embodiment of the diaphragm wall grabin a projection transverse to the course of the diaphragm wall;

FIG. 6 shows the diaphragm wall grab according to FIG. 5 in side viewfrom a viewing direction along the diaphragm wall.

The diaphragm wall grab shown in FIG. 1 has a guide body 11 formed by anouter frame 12. An inner body 10 with hinged grab shovels 1 andhydraulic operating device 2 is located therein. The inner body 10 ishinged within the guide body 11 in transverse direction to the verticalcourse of the diaphragm wall 40 by means of horizontal journals 20located in the direction of the diaphragm wall 40. Hydraulic swivellingmeans 30 are provided between the guide body 11 and the inner body 10.Furthermore, detectors 25 to control the vertical position of saidbodies are arranged at the inner body 10 and/or the guide body 11. Via asignal line the detector(s) 25 is/are permanently connected to a controldevice which is governed by the detector(s) and actuates the swing means30.

A depth measuring unit (not shown) may be allocated to the diaphragmwall grab, with means provided by which the indication of the positiondetector 25 and the indication of the depth measuring device can bemapped on each other. Additionally, further means for an overridingmanual regulative operation from the excavator control stand (not shown)can advantageously be allocated to the mechanisms 30 for swivelling theinternal body 10 or to the governing control device; with these meansthe position of the inner body 10 can be adjusted relative to the guidebody 11 in accordance with the position indication of the positiondetector 25.

As means for mutually swivelling the guide body 11 and the inner body 10a piston/cylinder-unit 30 is hinged to the left and to the right side ofthe frame 12 of the guide body, it interacts with an articulated leverarrangement 32 which is also pivoted at the frame 12 and has a cam 33which can be set in reciprocating swivelling movements. The cam engagesinto a U-shaped guidance 34 of the inner body 10 and swivels it, inaccordance with the position of the cam 33, relative to the guide body11 from the orthogonal position shown in FIGS. 2 and 6 into a differentswivelling position corresponding to the adjustment angle α shown inFIGS. 3 and 4. As can be taken from FIGS. 1, 2, 5, and 6 the guide body11 of the diaphragm wall grab is suspended in a rope 3. A comparison ofthe diaphragm wall grabs according to FIGS. 1 and 5 shows slightdifferences. The grab according to FIG. 5 is a comparatively heavierconstruction having a reinforced frame 12 of the outer guide body 11. Init the inner body 10 is hinged in the journals 20 in transversedirection to that of the slot. In contrast to the suspended arrangementaccording to FIGS. 1-4 the hydraulic cylinders 30 are arranged in astanding position. This is a purely mechanical measure within thediscretion of the technical designer. As for the rest, the embodimentsaccording to FIG. 1 and FIG. 5 have the same functions. According to theillustration of FIG. 1, the inner body 10 of the grab is preferablyprovided with an angle measuring device 25, and the indication of thedeviation can be combined with a depth measuring device so that thedeviation can be allocated to the corresponding slot depth and indicatedin the control panel. The adjustment via the lever system 32 isabsolutely uncomplicated, scarcely in need of maintenance and operatesat high accuracy. The adjustment members 30 may consist of a cylinderbody having a central cylinder bottom out of which two piston rods canbe extended independently of each other, one of them being hinged to theouter body 11 of the grab and the other one to the inner body 10 of thegrab. As can be seen in FIGS. 3 and 4, a horizontal swing in onedirection can be effected up to angle α if both piston rods are extended(FIG. 3), and in case both piston rods are retracted a swing in theopposite direction up to angle α can be carried out. In this connection,the hydraulic control of the adjustment cylinders can be designed suchthat both a continuous adjustment in both directions and a definedcentral or neutral position may be selected by the operator at will.

Owing to the articulated arrangement the hydraulic diaphragm wall grabaccording to the present invention is an extremely uncomplicated andsturdily built device and makes it possible to adjust the advancedirection of the grab shovels either fully automatic or manually. Inthis respect, the present invention perfectly fulfils the object statedin the beginning of this specification.

I claim:
 1. A process for maintaining a vertical excavating direction ofa diaphragm wall during excavation with a hydraulic diaphragm wallgrabber cooperating with an excavator and having an outer guide body, aninner body mounted in the outer guide body and a grabber appliancemounted to the inner body, said process comprising:detecting, with aninclination detector, an inclination of at least one of the inner bodyand the outer guide body relative to a vertical direction; controlling,with a control unit operatively connected to the inclination detectorand at least one of the inner body and the outer guide body, anorientation of at least one of the inner body and the outer guide bodyso as to compensate for deviation of the at least one of the inner bodyand the outer guide body to which the control unit is operativelyconnected by swiveling the inner body relative to the outer guide bodyin a direction opposite to a direction of the deviation.
 2. A process asrecited in claim 1, further comprisingmanually overriding, from acontrol panel of the excavator, the orientation compensation control ofthe control unit.
 3. A process as recited in claim 1, furthercomprisingdetecting, with a depth detection unit operatively connectedto the diaphragm wall grabber and to the control unit, a depth of thediaphragm wall.
 4. A device for maintaining a vertical excavatingdirection of a diaphragm wall, said device comprising:an outer guidebody; an inner body mounted in said outer guide body; at least one grabshovel hingedly mounted to said inner body; at least one horizontaljournal connecting said inner body to said outer guide body; a hydraulicswivel mechanism operatively connected between said inner body and saidouter guide body; an inclination detector operatively connected to atleast one of said inner body and said outer guide body for detecting anorientation of said at least one of said inner body and said outer guidebody relative to a vertical direction; and a control unit, operativelyconnected to said inclination detector and said at least one of saidinner body and said outer guide body, for operating said hydraulicswivel mechanism to control an orientation of said at least one of saidinner body and said outer guide body so as to compensate for deviationof said at least one of said inner body and said outer guide body toswivel the inner body relative to the outer guide body in a directionopposite to a direction of the deviation.
 5. A device as recited inclaim 4, further comprisingmeans formanually overriding, from a controlpanel of the excavator, the orientation compensation control of thecontrol unit.
 6. A device as recited in claim 5, whereina U-shaped guideis mounted on said inner body; and said hydraulic swivel mechanismcomprises a hydraulic piston-and-cylinder unit hinged to said outerguide body, an articulated lever arrangement pivotally mounted to saidouter guide body and operatively connected to said hydraulicpiston-and-cylinder unit, and a cam mounted to said articulated leverarrangement and disposed in said U-shaped guide.
 7. A device as recitedin claim 4, further comprisinga depth measuring unit, operativelyconnected to the diaphragm wall grabber and to the control unit, formeasuring a depth of the diaphragm wall.
 8. A device as recited in claim7, whereina U-shaped guide is mounted on said inner body; and saidhydraulic swivel mechanism comprises a hydraulic piston-and-cylinderunit hinged to said outer guide body, an articulated lever arrangementpivotally mounted to said outer guide body and operatively connected tosaid hydraulic piston-and-cylinder-unit, and a cam mounted to saidarticulated lever arrangement and disposed in said U-shaped guide.
 9. Adevice as recited in claim 4, whereina U-shaped guide is mounted on saidinner body; and said hydraulic swivel mechanism comprises a hydraulicpiston-and-cylinder unit hinged to said outer guide body, an articulatedlever arrangement pivotally mounted to said outer guide body andoperatively connected to said hydraulic piston-and-cylinder unit, and acam mounted to said articulated lever arrangement and disposed in saidU-shaped guide.